Protonated indole phthalides and naphthalides

Abstract

This invention relates to protonated compounds of the formula: ##SPC1## Wherein A is a radical selected from ##SPC2## X represents the atoms necessary to complete a ring-closing moiety selected from phthalide and naphthalide; and Z is an anion derived from a protic acid. These compounds are useful as intermediates in the preparation of phthalide and naphthalide indicator dyes.

What is claimed is: 
     
       1. A compound of the formula ##SPC92## wherein R 1  is hydrogen, methoxy, carboxy, --NHSO 2  R wherein R is selected from alkyl having 1 to 18 carbon atoms and phenyl substituted with alkyl wherein said alkyl substituent has 1 to 18 carbon atoms or --SO 2  NHR wherein R has the same meaning given above; R 2  is hydrogen, alkoxy containing 1 to 12 carbon atoms, carboxy or cyano; X represents the atoms necessary to complete a ring-closing moiety selected from phthalide and naphthalide; an Z is an anion derived from a protic acid having a pKa less than 4 selected from toluene-para-sulfonic acid and sulfuric acid, at least one of said R 1  and R 2  being hydrogen.   
     
     
       2. A compound as defined in claim 1 wherein said protic acid is toluene-para-sulfonic acid. 
     
     
       3. A compound as defined in claim 1 wherein X represents the atoms necessary to complete naphthalide. 
     
     
       4. The compound ##SPC93## 
     
     
       5. The compound ##SPC94## 
     
     
       6. The compound ##SPC95## 
     
     
       7. The compound ##SPC96## 
     
     
       8. The compound ##SPC97## 
     
     
       9. The compound ##SPC98## 
     
     
       10. The compound ##SPC99## 
     
     
       11. The compound ##SPC100## 
     
     
       12. The compound ##SPC101##